In a normal voice conversation, a user does not issue a voice continuously all the way. A phase during which a voice is not issued is referred to as an inactive voice phase. In normal cases, a whole inactive voice phase of both conversation parties will exceed 50% of a total voice encoding time length of both parties. In the non-active voice phase, it is the background noise that is encoded, decoded and transmitted by both parties, and the encoding and decoding operations on the background noise waste the encoding and decoding capabilities as well as radio resources. On basis of this, in a voice communication, the Discontinuous Transmission (DTX for short) mode is generally used to save the transmission bandwidth of the channel and device consumption, and few inactive voice frame parameters are extracted at the encoding end, and the decoding end performs Comfort Noise Generation (CNG for short) according to these parameters. Many modern voice encoding and decoding standards, such as Adaptive Multi-Rate (AMR) Adaptive Multi-Rate Wideband (AMR-WB) etc., support DTX and CNG functions. When a signal of an inactive voice phase is a stable background noise, both the encoder and the decoder operate stably. However, for an unstable background noise, especially when the noise is large, the background noise generated by these encoder and decoder using the DTX and CNG methods is not very stable, which will generate some bloop.